Effect of Strain Rate on the Microstructure and β-Texture Evolutions in β-Processed Forging of a Near-β Titanium Alloy

Abstract:

The effect of strain rate on the β texture evolution during two-step hot forging of Ti-6246 alloy was investigated. The two-step forging consisted of 15% or 50% prior-β forging at 980°C and subsequent 60% or 25% forging at 870°C in the (α + β) dual-phase region. The total compression ratio was 75%, and the investigated strain rates were 0.01 and 1.0 s⁻¹. The β forging texture showed typical {001} and {111} body-centered cubic textures. With increasing compression ratio in the (α + β) region and at a strain rate of 0.01 s⁻¹, the amount of precipitated α phase increased. Dynamic recrystallization was rarely observed after forging in the (α + β) region at a strain rate of 0.01 s⁻¹. Large amounts of α precipitates lowered the {001} β texture intensity through slip transmission between the α and β phases under the Burgers orientation relationship. However, in specimens forged at a strain rate of 1.0 s⁻¹, as the compression ratio in the β single-phase region increased, the growth of dynamic-recrystallized β grains was promoted at the prior-β grain boundaries, where α-phase precipitation was not substantial. These effects resulted in a higher {001} texture intensity of the β phase in specimens forged at 1.0 s⁻¹ compared with that of the β phase in specimens forged at 0.01 s⁻¹.

• Periodical: Materials Science Forum (Volume 1016)
• Pages: 882-887
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.1016.882
• Online since: January 2021
• Authors: Ling Jian Meng*, Tomonori Kitashima
• Keywords: Hot Forging, Phase Transformation, Strain Rate, Texture, Titanium Alloys

References

[1] J.O. Peters, G. Lutjering, Comparison of the Fatigue and Fracture of α+β and β Titanium Alloys, Metall. Mater. Trans. A, 32 (2001), 2805–2818.

[2] C. Sauer, G. Luetjering, Thermo-mechanical processing of high strength β-titanium alloys and effects on microstructure and properties, J. Mater. Process. Technol., 117 (2001), 311–317.

DOI: 10.1016/s0924-0136(01)00788-9

[3] E.A. Calnan, C.J.B. Clews, LXV. The development of deformation textures in metals.—Part II. Body-centred cubic metals, London, Edinburgh, Dublin Philos. Mag. J. Sci., 42 (1951), 616–635.

DOI: 10.1080/14786445108561277

[4] C.R. Weinberger, B.L. Boyce, C.C. Battaile, Slip planes in bcc transition metals, Int. Mater. Rev., 58 (2013), 296–314.

DOI: 10.1179/1743280412y.0000000015

[5] F. Chaussy, J.H. Driver, Evolutions microstructurales en compression uniaxiale à chaud de l'alliage β-Cez, Rev. Metall. Cah. D'Informations Tech., 93 (1996), 1057–1066.

DOI: 10.1051/metal/199693091057

[6] K. Li, P. Yang, The formation of strong {100} texture by dynamic strain-induced boundary migration in hot compressed Ti-5Al-5Mo-5V-1Cr-1Fe alloy, Metals (Basel), 7 (2017), 1–8.

DOI: 10.3390/met7100412

[7] T. Furuhara, B. Poorganji, H. Abe, T. Maki, Dynamic Recovery and Recrystallization in Titanium Alloys by Hot Deformation, JOM, 59 (1), (2007), 64-67.

DOI: 10.1007/s11837-007-0013-8

[8] L. Meng, T. Kitashima, T. Tsuchiyama, M. Watanabe, Effect of α precipitation on β texture evolution during β-processed forging in a near-β titanium alloy, Mater. Sci. Eng. A, 771 (2020), 138640.

DOI: 10.1016/j.msea.2019.138640

[9] S. Le Corre, R. Forestier, F. Brisset, M. Mathon, D. Solas, Influence of β‐Forging on Texture Development In Ti 6246 Alloy, in: Proc. 13th World Conf. Titan., Wiley Online Library, (2016), p.757–764.

DOI: 10.1002/9781119296126.ch127

[10] J.K. Fan, H.C. Kou, M.J. Lai, B. Tang, H. Chang, J.S. Li, Hot deformation mechanism and microstructure evolution of a new near β titanium alloy, Mater. Sci. Eng. A, 584 (2013), 121–132.

DOI: 10.1016/j.msea.2013.07.019